Alternatively, you can bring your idea to the
Collectibles section of this forum. You can solicit invaluable advice, suggestions, interest from Bitcoin community members who like collecting Bitcoin-related stuff, many of whom
experts.
It's best if you come up with a detailed design or a sample layout for them to check out. You can make changes based on the feedback. Perhaps you can consider creating a series of designs with a limited number of release per design.
Good luck! And you have to accept Bitcoin payments, too, by the way.